I don't know where you are but Castle Hill Toyota in Sydney is an import specialist. I went in there the other day asking for a idler arm for an RA28 and a dizzy cap for a GA70. Walked out with the dizzy cap and drove home with sloppy stearing.
They stock all the major servicing type parts but I doubt they would have a spare block in there.
There is plenty of these engines around, so the parts that aren't required for major type servicing aren't too difficult to come by.
These motors are good for about 150kw at the wheels. If you want more, you will need to consider a bigger turbo/s.